This disclosure relates generally to optical elements located downhole in a fluid system, and more particularly concerns use of a photo-catalytic process to prevent an optical element in a wellbore fluid system from being obscured or clouded by debris or contaminants contained in the fluid stream.
The application of many downhole optical techniques requires transparent optical elements that separate a fluid to be measured or analyzed from the measurement system. It is important for optical elements, including windows, lens or lens systems, and lighting systems, to remain clear. In many optical applications, the optical elements may become dirty by various components and material contained in the fluid. An optical element that becomes clouded or obscured will prevent an optical system from performing optimally. In some applications, like downhole fluid analysis, replacement or cleaning of the optical element may be impracticable, expensive and may delay operations.
It is important to have a method to clean the optical elements in-situ or prevent them from becoming obscured in-situ without needing to raise them to the surface. A substantial amount of time may be involved in lowering an optical element into the wellbore, raising the optical element out of the wellbore for cleaning, and then lowering it again after it is cleaned. Further, in passing through fluids on the way back down, the optical element may become obscured once again.
It is desirable to provide a downhole optical system capable of measuring and analyzing downhole conditions over an extended period of time without being rendered inoperative due to the adherence of obscuring downhole fluids or the action of caustic fluids. Specifically, it is desirable to develop a process to clean optical elements downhole that is capable of withstanding high pressures and high temperatures.
The disclosure may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the disclosure being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.